CIPE - Olaf Titz This is an ongoing project to build encrypting IP routers. It works by tunneling IP packets in encrypted UDP packets. The protocol is designed to be lightweight and simple. Special care has been taken to make this work over dynamic addresses, NAT and SOCKS proxies.
Implementations are currently available for Linux and Windows. The Windows stuff is being developed by Damion K. Wilson and can be found on the CIPE for Windows site.